


The Beating of Your Heart

by ArcticCalamity



Category: Undertale (Video Game)
Genre: F/M, Oral, Restraints, Tentacles, magic use
Language: English
Status: Completed
Published: 2015-12-09
Updated: 2015-12-09
Packaged: 2018-05-05 18:38:37
Rating: Explicit
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 1
Words: 2,057
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/5386262
Author URL: https://archiveofourown.org/users/ArcticCalamity/pseuds/ArcticCalamity
Summary: <blockquote class="userstuff">
              <p>A surprise for your sweet, skeleton boyfriend ended up better than you expected.</p>
            </blockquote>





	The Beating of Your Heart

**Author's Note:**

> Of-age reader, dfab
> 
> I still want to fuck the skeleton what else is new. Enjoy your ghost tentacles you filthy sinners.

You took a deep breath as you looked in the mirror. Your hair was perfect, your clothes looked great, so why were you so nervous? Your gut was aching like someone had kicked you and you sighed. You turned away from the mirror and went to sit on Sans’ bed. You knew exactly why you were nervous. You had been dating the skeleton for a while, and this wasn’t the first time you had slept with him. This was, however, the first time you were going to be surprising him. You knew this was when he would be coming home and you had taken care to have Undyne drag Papyrus away for cooking lessons, leaving the house empty. Perfect. You had made his bed and were sitting back on it now, hugging your knees. The air was chilly around you and you hugged yourself. You had on your best lingerie, the set that you knew Sans loved the best, but you always forgot how cold it was in the house. Your heart was pounding in your chest as you thought about your boyfriend coming home, finding you scantily clad and lounging in his bed.

You could hear your breath in the stillness of the air. Your ears were listening for any small sign that he was home. Soon, there was a small click from the front door as it opened. Your heart was fluttering wildly in your chest as you did your best to pose on his bed. You were going for some sort of sultry look, but some part of you thought you probably looked ridiculous. You inhaled deeply as footsteps moved up the stairs. Sans opened the door and the look on his face was absolutely delicious. At first it was shock, then confusion, but there was that look he gave you whenever he was about to bang you senseless. It was hot and wild desire that was spread across his face and he grinned as he shut the door.

“Why, hello there,” he said. 

“I’ve been waiting for you.”

“I can see that. I hope you weren’t too bonely without me.” He winked as he moved over to the bed. He pushed you down, pressing his face to your mouth. He couldn’t kiss, obviously, but you loved the feeling of him pressed against you, of his breath on your face and his bones on your arms as he ran his fingers over you. He pulled back and you exhaled shakily, the excitement still coursing through your veins. He slipped his jacket off, leaving him in just his sweater and shorts, before holding up his hand. Your breath caught in your throat. You knew exactly what he was going to do and you were ready. The air in the room became heavy and thick as his right eye went dark. Blue magic glowed around his bones and in his eye as he brought the hand close to your chest. As soon as he touched your bare skin a part of you exploded like fireworks. Everything about you was tingling, all the way down to your soul. It was as though you weren’t entirely yourself anymore – you and Sans were together in that moment. Your desire was hot in your mind, though you realized some of the feeling you had was Sans as well, and all you wanted was for him to push you down and fuck you until you couldn’t move.

“Beg.” Sans’ voice was low and hard and hearing it made your muscles twinge near your hips. You forgot that along with that magic came his ability to hear you, to feel you. He wasn’t just a part of you, you were a part of him. You swallowed, but everything felt thick in your throat.

“Please…Sans…” you managed. He shook his head.

“C’mon. I know you can do better than that.”

Everything felt hot and tight, squeezing inside you. Your words felt so small, lost in everything, in the magic. But Sans knew that. He wanted to hear you regardless. You swallowed again.

“Please fuck me…tie me up and wreck me. Please. I need you.” 

Sans smiled and released you from his magic, letting it still float through the air. You took a deep breath, letting the oxygen return to your lungs. Desire pooled in your stomach and you looked at him hungrily. The magic swirled around him and you expected it to condense on his pelvis, forming into the dick that he usually used. However, this time it solidified behind him, stringing out into multiple glowing blue tentacles. Heat rushed to your face.

“Sans…what are those?” You asked. He was still grinning.

“An experiment,” he said. “I’ve been wanting to try something new.” Your heart skipped a beat as one of the tendrils reached out and slid over your skin. It felt a lot like his dick, warm and smooth. In a second, multiple tentacles were wrapping around your arms and legs, pressing you hard against the bed. Your breath caught in your chest as you were pinned down, watching as a long, blue tongue fell from Sans’ mouth. You could almost feel it even before it touched your skin, starting at your stomach and tracing a long, wet line to your chest. He pushed your bra up with one hand, letting his fingers trace over your smooth curves and the slight bump of your nipple. You bit your lip as he flicked over it and pinched it. He ran his tongue along the underside before letting it rub over where his hand had been holding. A soft moan escaped your lips and you laid your head back, letting him touch and explore the skin he’d held so many times. Sans chuckled against your skin and moved his mouth back down, licking and nipping as he got closer and closer to your legs. He pressed his mouth against the outside of your panties and you bucked your hips against him. His tentacles tightened and he pulled away, giving you a serious look.

“If you want a reward, you have to be good,” he warned. You nodded. He moved his face back to your panties and pressed himself against them. His tongue snuck out from his maw and slid over the top of you. It brushed against your clit through the fabric and you bit your lip again, moaning softly. His left hand was stroking the inside of your thigh and his right one busied itself with rubbing your folds through your underwear. You wanted him inside you, to fill you up and make you forget the world. You thought you might melt when he pulled the fabric aside and gently ran his tongue over you. Another tentacle found its way towards you, curling around one of your breasts and squeezing. The tip of it pressed up against your nipple and rubbed gently. Sans’ tongue was moving against you now, sliding over your wetness and your clit and you groaned, letting the pleasure fill you. You kept your hips pressed against the bed, not wanting to move in case that would make him stop again. Your muscles trembled as you desperately wanted to buck against him, to press him closer. The tentacles shifted on your legs, keeping you pressed firmly and for a minute you wondered if Sans could still feel you. He used his hands for a moment to remove your underwear, leaving your lower half bare.

His tongue slid inside you and you gasped, the cool appendage sending shivers down your spine. It wiggled against your walls, pressing in all the right spots and moving against you until you thought you might scream. Then, he stopped. Sans pulled his face away, the bones of his jaw still covered in your juices. He ran his hand over his face to wipe some of it away before licking it from his fingers with his eyes trained on yours. You felt yourself tremble as he lapped up your liquid with his glowing tongue. More magic swirled around him and your stomach leapt. He was going to pull out his dick and finish you now. Excitement jumped through you and you grinned. All it did, though, was form more tentacles. They moved over you with Sans standing at the end of the bed, smiling and watching. One shoved itself into your mouth, another started fondling your other breast, and a third one rubbed itself over your thighs. You tried to gasp, but all that did was push the large tendril further into your mouth. You sucked on it gently, your saliva dripping over it and out of your mouth as it moved in and out. You whined at Sans, a desperate plea in your eyes. Then, the tentacle near your legs pushed inside of you.

You moaned as the thick magic pumped in and out of you, keeping a fast pace despite just starting. Your body was on fire from the treatment, from the sensation of everything rubbing against you at once. Your head was spinning as the tentacle filled you and pressed into you, moving hard and fast until you felt yourself nearing your peak, everything swirling around you in a mess of moans and pants and pleasure. You grew closer and closer, knowing that soon you’d hit the edge and spiral over. Then, he stopped again, and you felt yourself crash down, unsatisfied. You looked at him, horrified and betrayed. Sans was still grinning as the tentacles stopped moving. You moved your hips weakly, but nothing happened. The skeleton was still as he watched you fall from your high. Your breath heaved in your chest as he stepped towards you. He ran his hands over your stomach. One slipped down and lazily traced your sensitive clit, sending jolts through you. You wanted to speak, to ask him why he stopped, but something told you if you did he would stop touching you altogether and you couldn’t handle that. You needed him to run his hands over you, to fuck you, to finish you. Your insides were screaming for the release you’d almost had.

“Sans…” you whispered as a test. He didn’t stop the movement of his hand on your clit, so you took that as a sign to continue. “Please…fuck me. Take me. I need your weird magic dick inside me, please.”

“You think my dick is weird?” He laughed.

“It’s magic, Sans, it’s super weird. But that doesn’t mean I don’t want you to wreck me with it.”

“Fair enough,” he said as he grabbed your legs and pulled you to the end of the bed. Your hips were just at the edge, the perfect position for him to ram you. The magic solidified into the cock you had been waiting for, large, thick, and glowing blue, and he shoved it into you. You moaned loudly, glad that you had sent Papyrus away for the evening. He groaned as he entered you, bracing himself on your legs. He was bigger than the tentacle was, and soon you found yourself climbing to the peak again. He thrust in and out of you, pushing hard and fast. Your moans mixed together in the air and for a moment his concentration faded and the tentacles almost faded away. He held you tightly as he thrust faster, and you knew he was reaching his edge, too. You kept yourself at the peak as long as you could, mumbling out Sans’ name. He was whispering yours, too, and you thought the world might crumble apart. Finally, you couldn’t handle it any longer. You hit the edge and collapsed over it, riding out your orgasm as he thrust in again and came. He held you as close as he could as his liquid pumped into you. It spilled out past his dick and onto your ass and the bed, but you didn’t care. The magic dissipated and he collapsed into bed next to you. He dragged himself up to his pillow and wrapped an arm around you, pulling you close. Your muscles were weak, exhausted, and you were glad you were already laying down. Sans pulled the blanket out and spread it over you two. His breathing was heaving deep behind you as he relaxed and you fell asleep with your fingers intertwined with his.


End file.
